Most aesthetic issues for which patients seek treatment from physicians today are “more than skin deep.” For instance, gynoid lipodystrophy is a localized disorder of the subcutaneous tissue which leads to an alteration in the topography of the cutaneous surface (skin), or a dimpling effect. It is thought to be caused by increased fluid retention and/or proliferation of adipose tissue in certain subdermal regions, but known to be structure related. This condition, commonly known as cellulite, affects over 90% of post-pubescent women, and some men. Cellulite commonly appears on the hips, buttocks and legs, but is not necessarily caused by being overweight, as is a common perception. Cellulite is formed in the subcutaneous level of tissue, in the subdermal fat layer below the epidermis and dermis layers. In this region, fat cells are arranged in chambers surrounded by bands of connective tissue called septae. Cellulite is in part due to the parallel orientation of these fibrous septae structures. The fibrous structures being oriented in a parallel fashion (and perpendicular to the skin) is unique to women, whereas men typically have more random orientation of fibrous structures. This difference in fibrous structure may be in part or wholly responsible for the fact that men do not exhibit widespread cellulite in comparison to women. As the fat cells held within the perimeters defined by these fibrous septae expand they stretch the septae and surrounding connective tissue. Furthermore, adipocyte expansion from weight gain may also stretch the septae. Eventually this connective tissue contracts and hardens (scleroses) holding the skin at a non-flexible length, while the chambers between the septae continue to expand with weight gain, or water gain. This results in areas of the skin being held down while other sections bulge outward, resulting in the lumpy, ‘orange peel’ or ‘cottage cheese’ appearance on the skin surface. Even though obesity is not considered to be a root cause of cellulite, it can certainly worsen the dimpled appearance of a cellulitic region due to the increased number of fat cells in the region.
Over the years, a variety of approaches for treatment of skin irregularities such as cellulite and removal of unwanted adipose tissue have been proposed. For example, methods and devices that provide mechanical massage to the affected area, through either a combination of suction and massage or suction, massage and application of energy, in addition to application of various topical agents are currently available. Developed in the 1950's, mesotherapy is an injection of various treatment solutions through the skin that has been widely used in Europe for conditions ranging from sports injuries to chronic pain, to cosmetic procedures to treat wrinkles and cellulite. This treatment consists of the injection or transfer of various agents through the skin to provide increased circulation and the potential for fat oxidation, such as aminophylline, hyaluronic acid, Novocain, plant extracts and other vitamins. Another treatment entitled Acthyderm (Turnwood International, Ontario, Canada) employs a roller system that electroporates the stratum corneum to open small channels in the dermis, followed by the application of various mesotherapy agents, such as vitamins, antifibrotics, lypolitics, anti-inflammatories and the like.
Various other approaches employing dermatologic creams, lotions, vitamins and herbal supplements have also been proposed to treat cellulite. Private spas and salons offer cellulite massage treatments that include body scrubs, pressure point massage, essential oils, and herbal products using extracts from plant species such as seaweed, horsetail and clematis and ivy have also been proposed. Although a multitude of therapies exist, most of them do not provide a lasting effect on the skin irregularity, and some therapies may even cause the worsening of cellulite in certain patients. Yet other treatments for cellulite have negative side effects that limit their adoption. Regardless, most of these therapies require multiple treatments on an ongoing basis to maintain their effect at significant expense and with mixed results.
Massage techniques were tried as early as the 1930's as a method to increase lymphatic drainage and improve the appearance of cellulite. Mechanical massage devices, or Pressotherapy, have also been developed such as the “Endermologie” device (LPG Systems, France), the “Synergie” device (Dynatronics, Salt Lake City, Utah) and the “Silklight” device (Lumenis, Tel Aviv, Israel), all utilizing subdermal massage via vacuum and mechanical rollers. Other approaches have included a variety of energy sources, such as Cynosure's “TriActive” device (Cynosure, Westford, Mass.) utilizing a pulsed semiconductor laser in addition to mechanical massage, and the “Cellulux” device (Palomar Medical, Burlington, Mass.) which emits infrared light through a cooled chiller to target subcutaneous adipose tissue. The “VelaSmooth” system (Syneron, Inc., Yokneam Illit, Israel) employs bipolar radiofrequency energy in conjunction with suction massage to increase metabolism in adipose tissue, and the “Thermacool” device (Thermage, Inc., Hayward, Calif.) utilizes radiofrequency energy to shrink the subdermal fibrous septae to treat wrinkles and other skin defects. Other energy-based therapies such as electrolipophoresis, using several pairs of needles to apply a low frequency interstitial electromagnetic field to aid circulatory drainage have also been developed. Similarly, non-invasive ultrasound is used in the “Dermosonic” device (Symedex Medical, Minneapolis, Minn.) to promote increased fat reabsorption and drainage of retained fluids and toxins.
Methods and devices using ultrasound to disrupt subcutaneous tissues directly has been described in the known art. Such techniques may utilize a high intensity ultrasound wave that is focused on a tissue within the body, thereby causing a localized destruction or injury to cells. The focusing of the high intensity ultrasound may be achieved utilizing, for example, a concave transducer or am acoustic lens. Use of high intensity focused ultrasound to disrupt fat, sometimes in combination with removal of the fat by liposuction, has been described in the known prior art. Such use of high intensity focused ultrasound is distinguished from low acoustic pressure, therapeutic ultrasound.
Recently, it is has also become possible to exploit ultrasound waves for the purpose of disrupting tissue and tissue ablation without heating tissue to a level of tissue disruption. One such device is disclosed in U.S. Publication No. 2007/0055179 to Deem et al., incorporated herein by reference, which includes a method of infiltrating exogenous microbubbles into the target tissue, followed by applying low acoustic pressure ultrasound to the infiltrated tissue to cavitate the bubbles and destroy the target tissue without direct thermal injury to the dermis. Although low acoustic pressure ultrasound may somewhat heat tissue, the tissue is not heated sufficiently to cause direct tissue disruption or to enhance the ablation, and thus significantly reduces the risk of thermal damage to the dermis and associated structures (nerves, hair follicles, blood vessels). Liposonix (Bothell, Wash.) and Ultrashape (Tel Aviv, Israel) employ the use of focused ultrasound to destroy adipose tissue noninvasively. In addition, cryogenic cooling has been proposed for destroying adipose tissue.
Certain other techniques known as liposuction, tumescent liposuction, lypolysis and the like, target adipose tissue in the subdermal and deep fat regions of the body. These techniques may include also removing the fat cells once they are disrupted, or leaving them to be resorbed by the body's immune/lymphatic system. Liposuction is the most commonly performed cosmetic surgical procedure. Traditional liposuction includes the use of a surgical cannula placed at the site of the fat to be removed, and then the use of an infusion of fluids and mechanical motion of the cannula to break up the fatty tissue, and suction to “vacuum” the disrupted fatty tissue directly out of the patient. A variation on the traditional liposuction technique known as tumescent liposuction was introduced in 1985 and is currently considered by some to be the standard of care in the United States. It involves the infusion of tumescent fluids to the targeted region prior to mechanical disruption and removal by the suction cannula. The fluids may help to ease the pain of the mechanical disruption in some patients, while also swelling the tissues to make them more susceptible to mechanical removal. Various combinations of fluids may be employed in the tumescent solution including a local anesthetic such as lidocaine, a vasoconstrictive agent such as epinephrine, saline, potassium and the like. The benefits of such an approach are detailed in the articles, “Laboratory and Histopathologic Comparative Study of Internal Ultrasound-Assisted Lipoplasty and Tumescent Lipoplasty” Plastic and Reconstructive Surgery, September 15, (2002) 110:4, 11581164, and “When One Liter Does Not Equal 1000 Milliliters: Implications for the Tumescent Technique” Dermatol. Surg. (2000) 26:1024-1028, the contents of which are expressly incorporated herein by reference in their entirety.
Traditional fat extraction techniques such as liposuction, target deep fat and larger regions of the anatomy and can sometimes worsen the appearance of cellulite. The subdermal fat pockets remain and are accentuated by the loss of underlying bulk (deep fat) in the region. Many times liposuction is performed and patients still seek therapy for remaining skin irregularities, such as cellulite. The tools used in these procedures often have cutting edges and are intended to dissect the subcutaneous tissue and fibrous septae. Representative of such conventional tools is the “Toledo” cannula, pictured in Toledo L S, Mauas R, Complications of Body Sculpture: Prevention and Treatment. Clin Plastic Surg. 2006:33; 1-11.
There are physicians who target the more shallow subdermal fat pockets with liposuction, but at a higher risk of directly creating surface irregularities rather than treating them. Liposuction is not considered a viable treatment for cellulite for these reasons.
Another issue that must be factored in with liposuction is the amount of drugs infused with the tumescent solution. With large volume liposuctions, the Lidocaine infusion (for pain) can get up as high as 50 mg/kg, well above the intravascular toxicity limit of 7 mg/kg. The reason why liposuction patients can tolerate such a large volume of lidocaine is that the lidocaine is injected subcutaneously, is highly diluted, and is absorbed slowly over time. Thus, the actual systemic level of lidocaine is lower. However, in some cases lidocaine can spill over into the circulation and has resulted in patient mortality. For this reason, physicians monitor the Lidocaine does closely and often limit the area or treatment as a result.
More recently, energy sources have been added to the cannula to assist in the break-up and liquefication of the fat which in turn improves the ease of use. The “Lysonix” system (Mentor Corporation, Santa Barbara, Calif.) and “Vaser” system (Sound Surgical, Louisville, Colo.) utilize an ultrasonic transducer within the suction cannula to assist in tissue disruption (by cavitation of the tissue at the targeted site). Laser assisted cannula are offered by several companies including “Smartlipo” (Cynosure, Westford, Mass.), “Slimlipo” (Palomar Medical, Burlington, Mass.), and “Smoothlipo” (Eleme Medical, Merrimack, N.H.).
Subcutaneous dissection without fat aspiration is another approach to the treatment of skin irregularities such as scarring and dimpling. A technique called “subcision” was described by Orentreich in 1995. See Orentreich D S, Orentreich N. Subcutaneous incisionless surgery for the correction of depressed scars and wrinkles. Dermatological Surgery 1995 June; 21 (6): 543-9 This technique involves the insertion of a relatively large gauge needle subdermally in the region of dimpling or scarring, and then mechanically manipulating the needle below the skin to break up the fibrous septae in the subdermal region. In at least one known method of subcision, a solution containing an anesthetic (Lidocaine) and vasoconstrictor is injected into the targeted region and allowed to take effect. An 18-gauge needle is then inserted 10-20 mm below the cutaneous surface. The needle is then pulled back and directed parallel to the epidermis to create a dissection plane beneath the skin to essentially tear through, or “free up” the tightened septae causing the dimpling or scarring. Pressure is then applied to control bleeding acutely, and then by the use of compressive clothing following the procedure. While clinically effective in some patients, pain, bruising, bleeding and scarring can result. Other cutting implements include the aforementioned Toledo cannula, and several string or wire based cutting methods including the “Surgiwire” (Coapt Systems, Palo Alto, Calif.) and “ReleaseWire” (MicroAire, Charlottesville, Va.).
Cutting or relieving of the fibrous septae in the subdermal region by current subcision methods, is labor intensive, time consuming and techniques are highly variable. Significant physician time must be devoted to the procedure and there are technical limits as well as anesthetic limits to the size of a treatable area. There is a lack of clinical proof of that the techniques work for most patients and that the effects are lasting. For these reasons, and because of the potential side effects and extended time required for healing, subcision and liposuction have largely been abandoned as a treatment for cellulite in the United States.
In light of the foregoing, it would be desirable to provide a device and method for treating skin irregularities such as cellulite and to provide a sustained aesthetic result to a body region, such as the face, neck, arms, legs, thighs, buttocks, breasts, stomach and other targeted regions. It would also be desirable to provide device and method for treating skin irregularities that enhance prior techniques and make them less time intensive, more controlled, minimally invasive, and subject the patient to fewer side effects. The present invention adds a minimally invasive device and method for skin treatment by providing a controlled and less traumatic means for subcutaneous dissection and cutting of the fibrous septae in the subdermal fat or in the layer between the subdermal fat layers and the dermis, responsible for the appearance of cellulite. The device and method also provides an even level of cutting, parallel to the surface of the skin and with adequate skin traction, without further puncture or cutting of the skin. In addition to treating cellulite, this device and method may be used to treat hyperhidrosis, acne or other scars, and wrinkles. This treatment may also be used in conjunction with known methods of removing fat, skin tightening, or dermal thickening.